The diaphragm is the muscular wall separating the thoracic cavity from the abdominal cavity. The hiatus is a hole in the diaphragm through which the esophagus passes. When an internal tissue expands into an area it does not belong, it is known as a hernia. In a hiatal hernia, the stomach (which is normally in the abdominal cavity) extrudes through the hiatus and into the thoracic cavity. There are two types of hiatal hernias: (i) a sliding hiatal hernia, and (ii) a paraesophageal hiatal hernia. In a sliding hernia, the esophagus and stomach both move cranially through the hiatus. In a paraesophageal hernia, the stomach moves cranially through the hiatus relative to the esophagus. This movement can cause pinching or strangulation of the stomach which can cause localized ischemia which can be life threatening.
A hiatal hernia is caused by either a naturally large hiatus or increased abdominal pressure from pregnancy or obesity. In one example, a hiatal hernia can be diagnosed via x-ray with barium swallow, which allows visualization of the esophagus. In another example, a hiatal hernia can be diagnosed with endoscopy. When a physician believes that the stomach is at risk of constriction or strangulation, the hiatal hernia needs to be surgically repaired. The procedure to repair a hiatal hernia is referred to as reducing the hernia, which essentially entails putting the stomach back where it belongs. Open surgery is very invasive in this setting and should be avoided. Laparoscopic approaches allow for a ‘minimally invasive’ option. In the laparoscopic approach, a laparoscope is inserted through a 5-10 mm incision, and allows the surgeon to visualize the hernia while also repairing it. Advantages of laparoscopic surgery include smaller incision, less risk of infection, less pain and scarring, and a quicker recovery.
In paraesophageal hernia repair, a left side transthoracic laparoscopic access is performed. The hernia sac is dissected off the intrathoracic structures of the mediastinum. Once the sac is mobilized, it is excised down to the anterior wall of the esophagus and around the gastropharangeal junction. The esophagus is mobilized so that approximately 3 cm of the distal esophagus lies in the abdomen. Then the enlarged diaphragmic hiatus is closed primarily with suture for tension repair. The sutures are used to approximate the cura or pillars of the diaphragm. While such suturing is effective, it is time consuming and manually challenging. If this suturing step could be eliminated, it would greatly improve efficiencies in the operating room.
Laparoscopic surgery is another method to perform surgery in a minimally invasive way. A laparoscope is used where a camera is attached to a rod and passed into the abdominal cavity, allowing for 2D visualization. The endoscope is passed through a trocar. The abdominal cavity is insufflated with carbon dioxide. Through other incision sites various tools can be passed. The surgeon is in the field directly manipulating the tools, while a technician holds the endoscope. While this approach is minimally invasive with minimal cost requirements, the surgeon has limited range of motion at the surgical site resulting in a loss of dexterity. The surgeon also has a poor depth perception. Also, the tool endpoints move in the opposite direction to the surgeon's hands due to the pivot point of the device, making laparoscopic surgery a non-intuitive motor skill that is difficult to learn.
Robotic surgery is another method to perform surgery using very small tools attached to robotic arms. The surgeon controls the robotic arm with a computer, where she sits at the computer station away from the field and directs the movements of the robot with small surgical tools being attached to the arms of the robot. Small incisions are made to pass the three trocars into the abdominal cavity through which the endoscope (camera) allows the surgeon to see enlarged 3D images within the abdominal cavity of the patient. The robot matches the surgeon's hand movements to perform the procedure using the tiny movements. The 3D visualization and intuitive movement of the robotic arms make hiatal hernia more manageable. However, such a system comes with a substantial capital investment. As such, an improved device for repairing a hiatal hernia may be desirable.